21001220220020 has 24 divisors (see below), whose sum is σ = 44760809665824. Its totient is φ = 8275107668256.

The previous prime is 21001220220011. The next prime is 21001220220059. The reversal of 21001220220020 is 2002202210012.

It is a super-3 number, since 3×21001220220020³ (a number of 41 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21001220219977 and 21001220220004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7836274862 + ... + 7836277541.

It is an arithmetic number, because the mean of its divisors is an integer number (1865033736076).

Almost surely, 2^{21001220220020} is an apocalyptic number.

21001220220020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001220220020 is an abundant number, since it is smaller than the sum of its proper divisors (23759589445804).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21001220220020 is a wasteful number, since it uses less digits than its factorization.

21001220220020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15672552479 (or 15672552477 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 21001220220020 its reverse (2002202210012), we get a palindrome (23003422430032).

The spelling of 21001220220020 in words is "twenty-one trillion, one billion, two hundred twenty million, two hundred twenty thousand, twenty".